Police discovered and defused a homemade bomb planted near a hotel on the road leading from the Dagestani city of Buinaksk to the regional capital, Makhachkala, the Dagestani Interior Ministry said Monday.

Authorities said the bomb found Sunday near the Mercury hotel, located on the stretch of highway separating Dagestan's highlands from the lowlands, was the fourth terrorist act to be prevented in the restive southern region over the past week.

The bomb was made out of a four-liter canister filled with ammonium nitrates and aluminum powder, the ministry's press service said.

It also said that a suspected militant who had carried out rebel attacks in the Chechen capital of Grozny in 2001-2003 had been detained in the Khasavyurt region, which borders on Chechnya.

Dagestan has been shaken by violence, including attacks that have killed about 30 police and security officers this year alone. The motives behind the attacks are unclear: Some blame the killings on Islamic militants working in coordination with Chechen rebels, others pin it on people seeking vengeance for police brutality. Still others say the violence could be rooted in rivalry between Dagestan's more than 100 ethnic groups.